1
|
Song D, Liu H, Huang Y, Dongari-Bagtzoglou A, Lei Y. High-Throughput Monitoring of Pathogenic Fungal Growth Using Whole Slide Imaging for Rapid Antifungal Susceptibility Assessment. ANAL LETT 2023; 57:2412-2425. [PMID: 39005971 PMCID: PMC11245173 DOI: 10.1080/00032719.2023.2297301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 12/16/2023] [Indexed: 07/16/2024]
Abstract
Invasive fungal infections are a major health threat with high morbidity and mortality, highlighting the urgent need for rapid diagnostic tools to detect antifungal resistance. Traditional culture-based antifungal susceptibility testing (AFST) methods often fall short due to their lengthy process. In our previous research, we developed a whole-slide imaging (WSI) technique for the high-throughput assessment of bacterial antibiotic resistance. Building on this foundation, this study expands the application of WSI by adapting it for rapid AFST through high-throughput monitoring of the growth of hundreds of individual fungi. Due to the distinct "budding" growth patterns of fungi, we developed a unique approach that utilizes specific cell number change to determine fungi replication, instead of cell area change used for bacteria in our previous study, to accurately determine the growth rates of individual fungal cells. This method not only accelerates the determination of antifungal resistance by directly observing individual fungal cell growth, but also yields accurate results. Employing Candida albicans as a representative model organism, reliable minimum inhibitory concentration (MIC) of fluconazole inhibiting 100% cells of Candida albicans (denoted as MIC100) was obtained within 3h using the developed method, while the modified broth dilution method required 72h for the similar reliable result. In addition, our approach was effectively utilized to test blood culture samples directly, eliminating the need to separate the fungi from whole blood samples spiked with Candida albicans. These features indicate the developed method holds great potential serving as a general tool in rapid antifungal susceptibility testing and MIC determination.
Collapse
Affiliation(s)
- Donghui Song
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Haomin Liu
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Yikun Huang
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Anna Dongari-Bagtzoglou
- Department of Oral Health and Diagnostic Sciences, Health Center, University of Connecticut, Farmington, Connecticut, USA
| | - Yu Lei
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, USA
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA
| |
Collapse
|
2
|
Yerbanga IW, Nakanabo Diallo S, Rouamba T, Resendiz-Sharpe A, Lagrou K, Denis O, Rodriguez-Villalobos H, Montesinos I, Bamba S. Performances of disk diffusion method for determining triazole susceptibility of Aspergillus species: Systematic review. J Mycol Med 2023; 33:101413. [PMID: 37603962 DOI: 10.1016/j.mycmed.2023.101413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/05/2023] [Accepted: 07/11/2023] [Indexed: 08/23/2023]
Abstract
The therapeutic management of invasive aspergillosis should be guided by antifungal susceptibility testing (AFST). The disk diffusion (DD) method due to its simplicity and low cost could be an appropriate alternative to the reference methods (CLSI, EUCAST) which are not suitable for AFST in routine clinical microbiology laboratories, particularly in resource-constrained settings. This review summarizes the available data on the performance of the DD method in determining triazole susceptibility profile of Aspergillus species. The published articles on the performance of DD method for determining triazole susceptibility of Aspergillus spp. were systematically searched on major medical databases and Google Scholar. We identified 2725 articles of which 13 met the inclusion criteria. The overall average agreement value obtained between DD and CLSI broth microdilution (CLSI-BMD) methods for the itraconazole 10 µg disk (70.75%) was low especially when the medium used was not Mueller-Hinton (MH) agar. In contrast average agreement for the voriconazole 1 µg disk and the posaconazole 5 µg disk were > 94% regardless of media used. The correlation coefficient values between the DD and CLSI-BMD methods on MH agar were acceptable (≥ 0.71) for the itraconazole 10 µg disk and posaconazole 5 µg disk and good (≥ 0.80) for the voriconazole 1 and 10 µg disk. The reproducibility of the DD method regardless to the medium used was ≥ 82%. This systematic review shows that the disk diffusion method could be a real alternative for triazole antifungals susceptibility testing of Aspergillus spp.
Collapse
Affiliation(s)
- Isidore W Yerbanga
- Centre Hospitalier Universitaire Régional de Ouahigouya, 01 BP 36 Ouahigouya 01, Burkina Faso; Université Nazi Boni, 01 BP 1091 Bobo-Dioulasso 01, Burkina Faso.
| | - Seydou Nakanabo Diallo
- Université Nazi Boni, 01 BP 1091 Bobo-Dioulasso 01, Burkina Faso; Centre Muraz/Institut National de Santé Publique, 01 BP 390 Bobo-Dioulasso 01, Burkina Faso
| | - Toussaint Rouamba
- Clinical Research Unit of Nanoro, Institute for Research in Health Sciences, National Center for Scientific and Technological Research, BP: 218 Ouaga 11, Ouagadougou, Burkina Faso
| | | | - Katrien Lagrou
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium; Department of Laboratory Medicine and National Reference Center for Mycosis, Excellence Center for Medical Mycology (ECMM), University Hospitals Leuven, Leuven, Belgium
| | - Olivier Denis
- Department of Microbiology, CHU Namur site-Godinne, Université Catholique de Louvain, Rue Dr Gaston Therasse 1, 5530 Yvoir, Belgium; Ecole de Santé Publique, Université Libre de Bruxelles, Brussels, Belgium
| | - Hector Rodriguez-Villalobos
- Department of Microbiology, Cliniques Universitaires Saint-Luc - Université Catholique de Louvain, Avenue Hippocrate 10, 1200 Bruxelles, Belgium
| | - Isabel Montesinos
- Department of Microbiology, CHU Namur site-Godinne, Université Catholique de Louvain, Rue Dr Gaston Therasse 1, 5530 Yvoir, Belgium
| | - Sanata Bamba
- Université Nazi Boni, 01 BP 1091 Bobo-Dioulasso 01, Burkina Faso; Centre Hospitalier Universitaire Sourô Sanou, 01 BP 676 Bobo-Dioulasso 01, Burkina Faso
| |
Collapse
|
3
|
Wang HC, Hsieh MI, Choi PC, Wu WL, Wu CJ. Species distribution and antifungal susceptibility of clinical Aspergillus isolates: A multicentre study in Taiwan, 2016-2020. Mycoses 2023. [PMID: 37186489 DOI: 10.1111/myc.13593] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/10/2023] [Accepted: 04/12/2023] [Indexed: 05/17/2023]
Abstract
BACKGROUND Epidemiological knowledge is important to guide antifungal therapy. OBJECTIVE This multicentre study aimed to investigate the species distribution and antifungal susceptibility of Aspergillus isolates in Taiwan. METHOD Four hundred and ninety-two clinical Aspergillus isolates, collected during 2016-2020, were identified by calmodulin sequencing and tested for antifungal susceptibility using CLSI M38-A3. The Cyp51A sequences of azole-resistant Aspergillus fumigatus and Aspergillus flavus isolates were analysed. RESULTS This collection comprised 30 species from eight Aspergillus sections-Flavi (33.5%), Nigri (26.0%), Fumigati (24.2%), Terrei (10.0%), Nidulantes (5.1%), Circumdati (0.8%), Restricti (0.2%) and Aspergillus (0.2%). Sections Fumigati, Flavi and Terrei were primarily represented by A. fumigatus (99.2%), A. flavus (95.8%) and A. terreus (100%), respectively. Section Nigri comprised nine species, mostly A. welwitschiae (60.2%), A. niger (12.5%), A. brunneoviolaceus (10.9%) and A. tubingensis (10.2%). A. fumigatus (39.6%) and A. flavus (26.4%) predominated among 53 isolates from lower respiratory samples, whereas section Nigri species (46.2%) and A. terreus (29.2%) predominated among 65 isolates from ear samples. Reduced susceptibility to amphotericin B (minimal inhibitory concentration (MIC) > 1 μg/mL) was noted in A. flavus (7.0%), A. terreus (6.1%), A. nidulans and section Circumdati (A. flocculosus, A. subramanianii and A. westerdijkiae) isolates. Acquired azole resistance was observed in seven A. fumigatus (5.9%), all of which carried TR34 /L98H or TR34 /L98H/S297T/F495I mutation, and three A. flavus (1.9%), one of which carried G441S mutation. Reduced susceptibility to itraconazole (MIC >1 μg/mL) was noted in 55.5% of section Nigri isolates, mainly in A. welwitschiae, A. niger and A. tubingensis, whereas A. brunneoviolaceus, A. aculeatinus and A. japonicus were hypersusceptible to azoles. Anidulafungin was active against all isolates except for one isolate. CONCLUSIONS This study depicted the molecular epidemiology and species-specific characteristics of Aspergillus in Taiwan, which aids in appropriate antifungal therapy and underlines the need of speciation and susceptibility testing of disease-causing Aspergillus.
Collapse
Affiliation(s)
- Hsuan-Chen Wang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Ming-I Hsieh
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Pui-Ching Choi
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Wan-Lin Wu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Chi-Jung Wu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| |
Collapse
|
4
|
van de Sande WWJ. In vitro susceptibility testing for black grain eumycetoma causative agents. Trans R Soc Trop Med Hyg 2021; 115:343-354. [PMID: 33537781 PMCID: PMC8046409 DOI: 10.1093/trstmh/traa184] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/30/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022] Open
Abstract
Eumycetoma is a neglected tropical implantation mycosis characterized by large subcutaneous swellings. Inside the infected tissue, the causative agents are found in grains. The most common causative agents form black grains and are sterile upon isolation. In vitro susceptibility assays were developed for eumycetoma causative agents. They were based on the Clinical and Laboratory Standards Institute M38A protocol and modified to enable the use of hyphae as a starting inoculum. To ease endpoint reading, viability dyes such as resazurin or XTT have been used. So far the in vitro susceptibility assays developed have mainly been used to establish if causative agents are inhibited in growth by various antifungal agents, but not for clinical decision making. For drug discovery, the assay proved useful in determining which compounds were able to prevent hyphal growth. However, a clear correlation between in vitro inhibition in terms of the half maximal inhibitory concentration or 50% minimum inhibitory concentration (MIC50) and therapeutic efficacy assayed in a novel model system in terms of Galleria mellonella larval survival was not found. For clinical decision making, a range of MICs were found for each antifungal agent. However, no clinical breakpoints have been established for any of the causative agents. For itraconazole, the MIC50 of most causative agents was below the attainable serum levels, which might indicate that they are susceptible. However, before in vitro susceptibility can be used in clinical decision making for mycetoma, a correlation between MIC and clinical outcome needs to be made.
Collapse
Affiliation(s)
- Wendy W J van de Sande
- Erasmus Medical Center, University Medical Center Rotterdam, Department of Medical Microbiology and Infectious Diseases, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
| |
Collapse
|
5
|
Tryptic Stability and Antimicrobial Activity of the Derivatives of Polybia-CP with Fine-Tuning Modification in the Side Chain of Lysine. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-020-10129-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
6
|
Nuh A, Ramadan N, Schelenz S, Armstrong-James D. Comparative Evaluation of MIRONAUT-AM and CLSI broth microdilution method for antifungal susceptibility testing of Aspergillus species against four commonly used antifungals. Med Mycol 2020; 58:1085-1090. [DOI: 10.1093/mmy/myaa020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/05/2020] [Accepted: 04/02/2020] [Indexed: 11/14/2022] Open
Abstract
Abstract
The aim of this study was to evaluate a colorimetric method, MIRONAUT-AM, for determining susceptibility testing of anidulafungin, amphotericin, voriconazole, and itraconazole by comparing the minimum inhibitory (effective) concentrations (MICs/MECs) obtained by this method to those generated by the reference Clinical Laboratory Standard Institute (CLSI) broth microdilution method. In sum, 78 clinical isolates of Aspergillus species, nine of them non-wild type (non-WT) with itraconazole MIC ranging from 2 mg/l to >16 mg/l, were tested against above antifungals. A. fumigatus ATCC 204305 was used as a reference strain, and test was performed in accordance with slightly modified yeast susceptibility testing instruction of the manufacture; conidia suspension inoculum and alamarBlue concentration were optimized. These same isolates were referred to Bristol Mycology reference laboratory and tested by CLSI method. The MICs and MECs generated by the two methods were compared using concordance analysis. MIRONAUT-AM showed significant concordance (P < .0001) with CLSI method, and overall agreement was high (≥90%). In addition, MIRONAUT-AM produced echinocandin MECs results within 18–24 hours incubation time and correctly detected all non-WT isolates except one isolate. This colorimetric method is very promising and appears to be a suitable alternative susceptibility testing method to labor intensive broth microdilution reference method for Aspergillus species.
Collapse
Affiliation(s)
- Ali Nuh
- Department of Microbiology, Laboratory Medicine, Royal Brompton and Harefield NHS foundation trust, London
| | - Newara Ramadan
- Department of Microbiology, Laboratory Medicine, Royal Brompton and Harefield NHS foundation trust, London
| | - Silke Schelenz
- Department of Microbiology, Kings College Hospital, London
| | - Darius Armstrong-James
- Department of Microbiology, Laboratory Medicine, Royal Brompton and Harefield NHS foundation trust, London
| |
Collapse
|
7
|
Moribuchi H, Sato R, Matsushima S, Tominaga M, Sasaki J, Nakamura M, Sakazaki Y, Nishiyama M, Hoshino T, Kawayama T. Fulminant Tracheobronchial Aspergillosis in an Apparently Healthy Adult. Intern Med 2020; 59:1295-1298. [PMID: 32418954 PMCID: PMC7303448 DOI: 10.2169/internalmedicine.3857-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A 56-year-old healthy man who was a current smoker died from fulminant tracheobronchial aspergillosis despite a month of treatment with a combination of intravenous anti-fungal agents that had been started immediately after the diagnosis. This case report is important for understanding and managing fulminant Aspergillus infections in healthy subjects, although the pathogenesis and underlying pathways are still unknown.
Collapse
Affiliation(s)
- Hayato Moribuchi
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Rumi Sato
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
- Respiratory Medicine, Asakura Medical Association Hospital, Japan
| | | | - Masaki Tominaga
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Jun Sasaki
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Masayuki Nakamura
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Yuki Sakazaki
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Mamoru Nishiyama
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Tomoaki Hoshino
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| | - Tomotaka Kawayama
- Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Japan
| |
Collapse
|
8
|
Beardsley J, Halliday CL, Chen SCA, Sorrell TC. Responding to the emergence of antifungal drug resistance: perspectives from the bench and the bedside. Future Microbiol 2018; 13:1175-1191. [PMID: 30113223 PMCID: PMC6190174 DOI: 10.2217/fmb-2018-0059] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/01/2018] [Indexed: 12/15/2022] Open
Abstract
The incidence of serious fungal infections is increasing rapidly, and yet the rate of new drugs becoming available to treat them is slow. The limited therapeutic armamentarium is a challenge for clinicians, because the available drugs are often toxic, expensive, difficult to administer, ineffective or a combination of all four. Given this setting, the emergence of resistance is especially concerning, and a review of the topic is timely. Here we discuss antifungal drug resistance in Candida spp. and Aspergillus spp. with reference to the most commonly used first-line antifungal agents - azoles and echinocandins. We review the resistance mechanisms of the leading pathogens, how resistance can be identified in the diagnostic lab and the clinical implications of resistance once detected.
Collapse
Affiliation(s)
- Justin Beardsley
- Marie Bashir Institute for Infectious Diseases & Biosecurity, University of Sydney & Westmead Institute for Medical Research, Westmead, NSW, Australia
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Catriona L Halliday
- The Center for Infectious Diseases & Microbiology Laboratory Services, ICPMR Pathology West, New South Wales Health Pathology, Westmead, NSW, Australia
| | - Sharon C-A Chen
- Marie Bashir Institute for Infectious Diseases & Biosecurity, University of Sydney & Westmead Institute for Medical Research, Westmead, NSW, Australia
- The Center for Infectious Diseases & Microbiology Laboratory Services, ICPMR Pathology West, New South Wales Health Pathology, Westmead, NSW, Australia
| | - Tania C Sorrell
- Marie Bashir Institute for Infectious Diseases & Biosecurity, University of Sydney & Westmead Institute for Medical Research, Westmead, NSW, Australia
| |
Collapse
|
9
|
Pinto E, Monteiro C, Maia M, Faria MA, Lopes V, Lameiras C, Pinheiro D. Aspergillus Species and Antifungals Susceptibility in Clinical Setting in the North of Portugal: Cryptic Species and Emerging Azoles Resistance in A. fumigatus. Front Microbiol 2018; 9:1656. [PMID: 30083151 PMCID: PMC6065200 DOI: 10.3389/fmicb.2018.01656] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/03/2018] [Indexed: 12/14/2022] Open
Abstract
Aspergillus spp. are agents of a broad-spectrum of diseases among humans. Their growing resistance to azoles, the cornerstone in the management of human aspergillosis, is a worrisome problem around the world. Considering lack of data from Portugal on this topic, particularly from the northern region, a retrospective surveillance study was planned to assess frequency of cryptic Aspergillus species and azoles resistance. A total of 227 clinical isolates, mainly from the respiratory tract (92.1%), collected from three hospitals serving a population of about three million people, were studied for their epidemiology and antifungal susceptibility patterns determined by the E.DEF.9.3 protocol of EUCAST. Employing molecular methods, seven Aspergillus complexes were identified; Aspergillus fumigatus sensu stricto was the most frequent isolate (86.7%). A 7.5% prevalence of cryptic species was found; A. welwitschiae (A. niger complex-3.1%) and A. lentulus (A. fumigatus complex-2.2%) were the most frequent. Amongst cryptic species, it was found a percentage of resistance to voriconazole, posaconazole and isavuconazole of 47.1, 82.4, and 100%, respectively. Five A. fumigatus sensu stricto showed pan-azole resistance. Sequencing their cyp51A gene revealed the presence of one isolate with TR46/Y121F/T289A mutation and two isolates with TR34/L98H mutation. This study emphasizes the need to identify strains to the species level and to evaluate their antifungal susceptibility in all human originated Aspergillus spp. isolates, particularly those from invasive aspergillosis.
Collapse
Affiliation(s)
- Eugénia Pinto
- Laboratory of Microbiology, Biological Sciences Department, Faculty of Pharmacy of University of Porto, Porto, Portugal.,Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Matosinhos, Portugal
| | - Carolina Monteiro
- Laboratory of Microbiology, Biological Sciences Department, Faculty of Pharmacy of University of Porto, Porto, Portugal
| | - Marta Maia
- Laboratory of Microbiology, Biological Sciences Department, Faculty of Pharmacy of University of Porto, Porto, Portugal
| | - Miguel A Faria
- LAQV-REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Virgínia Lopes
- Microbiology Laboratory, Pathology Department, Centro Hospitalar do Porto, Porto, Portugal
| | - Catarina Lameiras
- Microbiology Service, Laboratorial Diagnostic Department, Instituto Português Oncologia do Porto Francisco Gentil, EPE (IPOFG-Porto), Porto, Portugal
| | - Dolores Pinheiro
- Laboratory of Microbiology, Service of Clinical Pathology, Centro Hospitalar S. João EPE, Porto, Portugal
| |
Collapse
|
10
|
Bernal-Martínez L, Alastruey-Izquierdo A, Cuenca-Estrella M. Diagnostics and susceptibility testing in Aspergillus. Future Microbiol 2016; 11:315-28. [PMID: 26848512 DOI: 10.2217/fmb.15.140] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Invasive aspergillosis is a major cause of morbidity and mortality in immunosuppressed patients. Early diagnosis and correct antifungal treatment have a direct impact on patient survival. A number of newer diagnostic procedures have been developed as alternatives to conventional microbiological methods. The detection of fungal components, largely antigens and DNA, are used in clinical laboratories to diagnose invasive aspergillosis. Other rapid diagnostic tests have been recently developed with promising results. However, antifungal resistance is becoming an emerging problem. The detection of this resistance is important to administer the proper antifungal agent. This text reviews the novelties on new diagnostics Aspergillus spp. PROCEDURES Intrinsic antifungal resistance and mechanisms of secondary resistance to triazoles in A. fumigatus are also reviewed.
Collapse
Affiliation(s)
- Leticia Bernal-Martínez
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Alastruey-Izquierdo
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Manuel Cuenca-Estrella
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
11
|
Chowdhary A, Singh PK, Kathuria S, Hagen F, Meis JF. Comparison of the EUCAST and CLSI Broth Microdilution Methods for Testing Isavuconazole, Posaconazole, and Amphotericin B against Molecularly Identified Mucorales Species. Antimicrob Agents Chemother 2015; 59:7882-7. [PMID: 26438489 PMCID: PMC4649204 DOI: 10.1128/aac.02107-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 09/27/2015] [Indexed: 12/13/2022] Open
Abstract
We compared EUCAST and CLSI antifungal susceptibility testing (AFST) methods for triazoles and amphotericin B against 124 clinical Mucorales isolates. The EUCAST method yielded MIC values 1- to 3-fold dilutions higher than those of the CLSI method for amphotericin B. The essential agreements between the two methods for triazoles were high, i.e., 99.1% (voriconazole), 98.3% (isavuconazole), and 87% (posaconazole), whereas it was significantly lower for amphotericin B (66.1%). Strategies for harmonization of the two methods for Mucorales AFST are warranted.
Collapse
Affiliation(s)
- Anuradha Chowdhary
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Pradeep Kumar Singh
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Shallu Kathuria
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Ferry Hagen
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands
| | - Jacques F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands
| |
Collapse
|
12
|
Comparative analysis of quinolone resistance in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese children and adults. BIOMED RESEARCH INTERNATIONAL 2015; 2015:168292. [PMID: 25756041 PMCID: PMC4338376 DOI: 10.1155/2015/168292] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/19/2014] [Accepted: 01/27/2015] [Indexed: 12/14/2022]
Abstract
The objective of this study was to compare quinolone resistance and gyrA mutations in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese adults who used quinolone in the preceding month and children without any known history of quinolone administration. The antimicrobial susceptibilities of 61 isolates from children and 79 isolates from adults were determined. The mutations in the quinolone resistance-determining regions in gyrA gene were detected by PCR and DNA sequencing. Fluoroquinolone resistance and types of gyrA mutations in isolates from children and adults were compared and statistically analyzed. No significant differences were detected in the resistance rates of ciprofloxacin and levofloxacin between children and adults among isolates of the two species (all P > 0.05). The double mutation Ser83→Leu + Asp87→Asn in the ciprofloxacin-resistant isolates occurred in 73.7% isolates from the children and 67.9% from the adults, respectively (P = 0.5444). Children with no known history of quinolone administration were found to carry fluoroquinolone-resistant Enterobacteriaceae isolates. The occurrence of ciprofloxacin resistance and the major types of gyrA mutations in the isolates from the children were similar to those from adults. The results indicate that precautions should be taken on environmental issues resulting from widespread transmission of quinolone resistance.
Collapse
|
13
|
Arendrup MC, Howard S, Lass-Flörl C, Mouton JW, Meletiadis J, Cuenca-Estrella M. EUCAST testing of Isavuconazole susceptibility in Aspergillus: comparison of results for Inoculum standardization using Conidium counting versus optical density. Antimicrob Agents Chemother 2014; 58:6432-6. [PMID: 25136005 PMCID: PMC4249446 DOI: 10.1128/aac.03779-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/08/2014] [Indexed: 11/20/2022] Open
Abstract
The EUCAST E.DEF9.1 standard recommends standardization of the inoculum concentration by conidium counting using a hemocytometer rather than a spectrophotometer. In this study, we investigated whether the choice of these methods influenced isavuconazole MICs. A blinded collection of 30 molecularly characterized azole-resistant isolates and 10 wild-type Aspergillus fumigatus isolates was shared with four different laboratories. Additionally, each laboratory selected approximately 100 A. fumigatus isolates and 50 isolates each of A. flavus, A. nidulans, A. niger, and A. terreus (1,237 isolates in total). Three laboratories (laboratories 1 to 3) used conidium counting. One laboratory standardized the inoculum using a spectrophotometer (that is, by use of the optical density [OD]) and is referred to as the OD laboratory. Correlation coefficients, intraclass correlation coefficients, and essential agreement were calculated, and 2-log-unit differences were assessed (paired t test). The MIC range for the blinded collection was 0.25 to 16 mg/liter, and a 1-dilution-step difference between the MIC50 and MIC90 across the four laboratories was detected and a 2-dilution-step difference between the modal MICs was detected. Compared to the results for laboratories 1 and 2, a significant correlation was found for the OD laboratory MIC data (correlation coefficients, 0.85 and 0.93, respectively; intraclass correlation coefficients, 0.88 and 0.96, respectively). The number of mutant isolates whose MICs overlapped those of the wild-type isolates was the lowest for the OD laboratory (14/30 [46.7%] mutant isolates), whereas the numbers were 18/30 (60%) isolates for laboratory 1, 17/30 (56.7%) isolates for laboratory 2, and 21/30 (70%) isolates for laboratory 3. For the A. flavus, A. fumigatus, A. nidulans, A. niger, and A. terreus isolates, comparative analysis again defined the MIC distributions from the OD laboratory to be in excellent agreement with those from laboratories 1 and 2 across all five Aspergillus spp. The findings suggest that EUCAST testing using OD determination is an appropriate alternative for standardization of Aspergillus inoculum concentrations.
Collapse
Affiliation(s)
- Maiken Cavling Arendrup
- Unit of Mycology and Parasitology, Statens Serum Institut, Department of Microbiological Surveillance and Research, Copenhagen, Denmark
| | - Susan Howard
- Department of Molecular and Clinical Pharmacology, Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Cornelia Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Manuel Cuenca-Estrella
- Department of Mycology, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| |
Collapse
|
14
|
Lago M, Aguiar A, Natário A, Fernandes C, Faria M, Pinto E. Does fungicide application in vineyards induce resistance to medical azoles in Aspergillus species? ENVIRONMENTAL MONITORING AND ASSESSMENT 2014; 186:5581-5593. [PMID: 24833021 DOI: 10.1007/s10661-014-3804-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 04/30/2014] [Indexed: 06/03/2023]
Abstract
This study assessed if the use of sterol demethylase inhibitor fungicides in vineyard production can induce resistance to azoles in Aspergillus strains and if it can induce selection of resistant species. We also tried to identify the Aspergillus species most prevalent in the vineyards. Two vineyards from northern Portugal were selected from "Vinhos Verdes" and "Douro" regions. The vineyards were divided into plots that were treated or not with penconazole (PEN). In each vineyard, air, soil, and plant samples were collected at three different times. The strains of Aspergillus spp. were isolated and identified by morphological and molecular techniques. We identified 46 Aspergillus section Nigri, eight Aspergillus fumigatus, seven Aspergillus lentulus, four Aspergillus wentii, two Aspergillus flavus, two Aspergillus terreus, one Aspergillus calidoustus, one Aspergillus westerdijkiae, one Aspergillus tamarii, and one Eurotium amstelodami. Aspergillus strains were evaluated for their susceptibility to medical azoles used in human therapy (itraconazole, posaconazole, and voriconazole) and to agricultural azoles (PEN) used in the prevention and treatment of plant diseases. The isolates showed moderate susceptibility to voriconazole. We did not observe any decrease of susceptibility to the medical azoles tested throughout the testing period in any of the treated plots, although some of the resistant species were isolated from there.
Collapse
Affiliation(s)
- Magali Lago
- CEQUIMED-UP/Serviço de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | | | | | | | | | | |
Collapse
|
15
|
Pastor FJ, Guarro J. Treatment of Aspergillus terreus infections: a clinical problem not yet resolved. Int J Antimicrob Agents 2014; 44:281-9. [PMID: 25190543 DOI: 10.1016/j.ijantimicag.2014.07.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 07/03/2014] [Accepted: 07/10/2014] [Indexed: 10/24/2022]
Abstract
Despite the use of recommended therapies, invasive infections by Aspergillus terreus show a poor response. For years, investigative studies on the failure of therapy of fungal infections have focused on in vitro susceptibility data. However, it is well known that low minimum inhibitory concentrations (MICs) are not always predictive of response to therapy despite a correct dosage schedule. Many experimental and clinical studies have tried to establish a relationship between MICs and outcome in serious fungal infections but have come to contradictory and even surprising conclusions. The success or failure of treatment is determined by many factors, including the in vitro susceptibility of the causative fungal isolate, the pharmacokinetics/pharmacodynamics of the drug used for treatment, pharmacokinetic variability in the population, and the underlying disease that patients suffer. To try to understand this poor response to treatment, available data on the in vitro susceptibility of A. terreus, the experimental and clinical response to amphotericin B, triazoles and echinocandins, and the pharmacokinetics/pharmacodynamics of these antifungals have been reviewed. Of special interest are the fungistatic activites of these drugs against A. terreus and the high interpatient variability of serum drug levels observed in therapy based on triazoles, which make monitoring of infected patients necessary.
Collapse
Affiliation(s)
- F Javier Pastor
- Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Spain
| | - Josep Guarro
- Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Spain.
| |
Collapse
|
16
|
Posteraro B, Sanguinetti M. The future of fungal susceptibility testing. Future Microbiol 2014; 9:947-67. [DOI: 10.2217/fmb.14.55] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT The antifungal treatment failures and the emergence of resistant fungal strains have stimulated the need for reproducible and clinically relevant antifungal susceptibility testing (AFST). While the standard reference methods are not intended for routine use, commercial methods are widely used for performing AFST. However, to accelerate AFST and to improve the detection of antifungal resistance, which is the most challenging goal of AFST, novel assays have been developed. Following brief drug exposures of fungal cells, the new antifungal susceptibility end points seem to provide a reliable means of identifying fungal isolates, which harbor mutations that have been associated with antifungal resistance. This article summarizes the recent progress in AFST that is destined to enhance its clinical utility in the near future.
Collapse
Affiliation(s)
- Brunella Posteraro
- Institute of Public Health, Section of Hygiene, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, Rome, Italy
| | - Maurizio Sanguinetti
- Institute of Microbiology, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| |
Collapse
|
17
|
Cryptic and rare Aspergillus species in Brazil: prevalence in clinical samples and in vitro susceptibility to triazoles. J Clin Microbiol 2014; 52:3633-40. [PMID: 25078909 DOI: 10.1128/jcm.01582-14] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus spp. are among the most common causes of opportunistic invasive fungal infections in tertiary care hospitals. Little is known about the prevalence and in vitro susceptibility of Aspergillus species in Latin America, because there are few medical centers able to perform accurate identification at the species level. The purpose of this study was to analyze the distribution of cryptic and rare Aspergillus species among clinical samples from 133 patients with suspected aspergillosis admitted in 12 medical centers in Brazil and to analyze the in vitro activity of different antifungal drugs. The identification of Aspergillus species was performed based on a polyphasic approach, as well as sequencing analysis of the internal transcribed spacer (ITS) region, calmodulin, and β-tubulin genes and phylogenetic analysis when necessary. The in vitro susceptibility tests with voriconazole, posaconazole, and itraconazole were performed according to the CLSI M38-A2 document (2008). We demonstrated a high prevalence of cryptic species causing human infection. Only three isolates, representing the species Aspergillus thermomutatus, A. ochraceus, and A. calidoustus, showed less in vitro susceptibility to at least one of the triazoles tested. Accurate identifications of Aspergillus at the species level and with in vitro susceptibility tests are important because some species may present unique resistance patterns against specific antifungal drugs.
Collapse
|
18
|
Calderone R, Sun N, Gay-Andrieu F, Groutas W, Weerawarna P, Prasad S, Alex D, Li D. Antifungal drug discovery: the process and outcomes. Future Microbiol 2014; 9:791-805. [PMID: 25046525 PMCID: PMC4144029 DOI: 10.2217/fmb.14.32] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
New data suggest that the global incidence of several types of fungal diseases have traditionally been under-documented. Of these, mortality caused by invasive fungal infections remains disturbingly high, equal to or exceeding deaths caused by drug-resistant tuberculosis and malaria. It is clear that basic research on new antifungal drugs, vaccines and diagnostic tools is needed. In this review, we focus upon antifungal drug discovery including in vitro assays, compound libraries and approaches to target identification. Genome mining has made it possible to identify fungal-specific targets; however, new compounds to these targets are apparently not in the antimicrobial pipeline. We suggest that 'repurposing' compounds (off patent) might be a more immediate starting point. Furthermore, we examine the dogma on antifungal discovery and suggest that a major thrust in technologies such as structural biology, homology modeling and virtual imaging is needed to drive discovery.
Collapse
Affiliation(s)
| | - Nuo Sun
- National Institutes of Health, Bethesda, MD, USA
| | | | - William Groutas
- Department of Chemistry, Wichita State University, Wichita, KS, USA
| | | | | | - Deepu Alex
- Department of Pathology, MedStar, Georgetown University Medical Center, Washington, DC, USA
| | - Dongmei Li
- Georgetown University Medical Center, Washington, DC, USA
| |
Collapse
|
19
|
Yang J, Chen Z, Ching P, Shi Q, Li X. An integrated microfluidic platform for evaluating in vivo antimicrobial activity of natural compounds using a whole-animal infection model. LAB ON A CHIP 2013; 13:3373-82. [PMID: 23824379 DOI: 10.1039/c3lc50264c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The nematode Caenorhabditis elegans is a useful model host for pathogenesis research that can be infected by a large number of human pathogens. Conventionally, nematode-pathogen infection assays are mainly performed on agar medium which are labor-intensive and time-consuming. To overcome these challenges, we develop for the first time an integrated microfluidic device for evaluating in vivo antimicrobial activity of natural compounds, which allows infection and anti-infection assays to be sequentially and automatically carried out in liquid medium. The device consists of a worm dispenser with 32 trap-construction chambers and concentration gradient generators, in which the processes of introduction, dispensation, confinement of worms in the chamber and drug delivery to the chamber can be integrated into a single device. In addition, the operation of the device is simple and does not require any expensive robotic fluid handling systems to dispense samples. To demonstrate the ability of this device, we devise an on-line screening experiment using a Caenorhabditis elegans-Staphylococcus aureus infection model and characterize the survival rate of the infected worms treated with antibiotics. Then, we applied the system to evaluate the antibacterial activity of several components of rhubarb: aloe-emodin, rhein and emodin at various concentrations. The device is able to load uniform worms into each chamber within 10 min and then generate various chemical concentrations automatically and simultaneously. Furthermore, the on-chip method only requires 6 h to establish the infection model and 48 h to perform the subsequent treatments. Based on the excellent advantages and scalable properties of microfluidics, the microfluidic platform holds a great potential in high-throughput screening for antimicrobials.
Collapse
Affiliation(s)
- Jianping Yang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, PR China
| | | | | | | | | |
Collapse
|
20
|
Abstract
Azole-resistant strains of Aspergillus have been reported from European and Asian countries at varying frequencies. Based on the limited rates of isolation of Aspergillus from clinical samples in routine practice and the limited number of the screening studies carried out so far, the true prevalence of triazole resistance and the rate of multiazole-resistant strains remain partly unknown. Also, available data are mostly for A. fumigatus (complex), thus the situation for non-fumigatus Aspergilli is less clear. In general, exposure of Aspergillus to antifungal agents via medical or environmental (agricultural) use of these compounds appears to have the possible major impact on acquisition of triazole resistance. Azole resistance in Aspergillus remains to be further elucidated by continued surveillance studies. Based on the possible association with agricultural azole use, environmental sampling appears significant as well.
Collapse
Affiliation(s)
- Sevtap Arikan-Akdagli
- Department of Medical Microbiology, Hacettepe University Medical School, Ankara, Turkey.
| |
Collapse
|
21
|
In vitro activity of a new oral glucan synthase inhibitor (MK-3118) tested against Aspergillus spp. by CLSI and EUCAST broth microdilution methods. Antimicrob Agents Chemother 2012; 57:1065-8. [PMID: 23229479 DOI: 10.1128/aac.01588-12] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MK-3118, a glucan synthase inhibitor derived from enfumafungin, and comparator agents were tested against 71 Aspergillus spp., including itraconazole-resistant strains (MIC, ≥ 4 μg/ml), using CLSI and EUCAST reference broth microdilution methods. The CLSI 90% minimum effective concentration (MEC(90))/MIC(90) values (μg/ml) for MK-3118, amphotericin B, and caspofungin, respectively, were as follows: 0.12, 2, and 0.03 for Aspergillus flavus species complex (SC); 0.25, 2, and 0.06 for Aspergillus fumigatus SC; 0.12, 2, and 0.06 for Aspergillus terreus SC; and 0.06, 1, and 0.03 for Aspergillus niger SC. Essential agreement between the values found by CLSI and EUCAST (± 2 log(2) dilution steps) was 94.3%. MK-3118 was determined to be a potent agent regardless of the in vitro method applied, with excellent activity against contemporary wild-type and itraconazole-resistant strains of Aspergillus spp.
Collapse
|
22
|
Purisco SU, Martins MA, Szeszs MW, Castro e Silva DM, Pukinskas SR, Bonfietti LX, Baez AA, Melhem MS. Comparison of the broth microdilution (BMD) method of the European Committee on Antimicrobial Susceptibility Testing and the Clinical Laboratory Standards Institute BMD method for non-Candida albicans and non-C. tropicalis bloodstream isolates from eleven. FEMS Yeast Res 2012; 12:890-6. [DOI: 10.1111/j.1567-1364.2012.00838.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sonia U. Purisco
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Marilena A. Martins
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Maria W. Szeszs
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Dulcilena M. Castro e Silva
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Sandra R.B.S. Pukinskas
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Lucas X. Bonfietti
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Andres A. Baez
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| | - Marcia S.C. Melhem
- Adolfo Lutz Institute; Coordination of Disease Control; Secretary of Health; Government of São Paulo State; São Paulo; Brazil
| |
Collapse
|
23
|
Combining microdilution with MicroResp™: Microbial substrate utilization, antimicrobial susceptibility and respiration. J Microbiol Methods 2012; 88:399-412. [DOI: 10.1016/j.mimet.2012.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 01/08/2012] [Accepted: 01/08/2012] [Indexed: 01/15/2023]
|
24
|
Campbell BC, Chan KL, Kim JH. Chemosensitization as a means to augment commercial antifungal agents. Front Microbiol 2012; 3:79. [PMID: 22393330 PMCID: PMC3289909 DOI: 10.3389/fmicb.2012.00079] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 02/15/2012] [Indexed: 11/13/2022] Open
Abstract
Antimycotic chemosensitization and its mode of action are of growing interest. Currently, use of antifungal agents in agriculture and medicine has a number of obstacles. Foremost of these is development of resistance or cross-resistance to one or more antifungal agents. The generally high expense and negative impact, or side effects, associated with antifungal agents are two further issues of concern. Collectively, these problems are exacerbated by efforts to control resistant strains, which can evolve into a treadmill of higher dosages for longer periods. This cycle in turn, inflates cost of treatment, dramatically. A further problem is stagnation in development of new and effective antifungal agents, especially for treatment of human mycoses. Efforts to overcome some of these issues have involved using combinations of available antimycotics (e.g., combination therapy for invasive mycoses). However, this approach has had inconsistent success and is often associated with a marked increase in negative side effects. Chemosensitization by natural compounds to increase effectiveness of commercial antimycotics is a somewhat new approach to dealing with the aforementioned problems. The potential for safe natural products to improve antifungal activity has been observed for over three decades. Chemosensitizing agents possess antifungal activity, but at insufficient levels to serve as antimycotics, alone. Their main function is to disrupt fungal stress response, destabilize the structural integrity of cellular and vacuolar membranes or stimulate production of reactive oxygen species, augmenting oxidative stress and apoptosis. Use of safe chemosensitizing agents has potential benefit to both agriculture and medicine. When co-applied with a commercial antifungal agent, an additive or synergistic interaction may occur, augmenting antifungal efficacy. This augmentation, in turn, lowers effective dosages, costs, negative side effects and, in some cases, countermands resistance.
Collapse
Affiliation(s)
- Bruce C. Campbell
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of AgricultureAlbany, CA, USA
| | - Kathleen L. Chan
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of AgricultureAlbany, CA, USA
| | - Jong H. Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of AgricultureAlbany, CA, USA
| |
Collapse
|
25
|
Abstract
Antifungal resistance continues to grow and evolve and complicate patient management, despite the introduction of new antifungal agents. In vitro susceptibility testing is often used to select agents with likely activity for a given infection, but perhaps its most important use is in identifying agents that will not work, i.e., to detect resistance. Standardized methods for reliable in vitro antifungal susceptibility testing are now available from the Clinical and Laboratory Standards Institute (CLSI) in the United States and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in Europe. Data gathered by these standardized tests are useful (in conjunction with other forms of data) for calculating clinical breakpoints and epidemiologic cutoff values (ECVs). Clinical breakpoints should be selected to optimize detection of non-wild-type (WT) strains of pathogens, and they should be species-specific and not divide WT distributions of important target species. ECVs are the most sensitive means of identifying strains with acquired resistance mechanisms. Various mechanisms can lead to acquired resistance of Candida species to azole drugs, the most common being induction of the efflux pumps encoded by the MDR or CDR genes, and acquisition of point mutations in the gene encoding for the target enzyme (ERG11). Acquired resistance of Candida species to echinocandins is typically mediated via acquisition of point mutations in the FKS genes encoding the major subunit of its target enzyme. Antifungal resistance is associated with elevated minimum inhibitory concentrations, poorer clinical outcomes, and breakthrough infections during antifungal treatment and prophylaxis. Candidemia due to Candida glabrata is becoming increasingly common, and C glabrata isolates are increasingly resistant to both azole and echinocandin antifungal agents. This situation requires continuing attention. Rates of azole-resistant Aspergillus fumigatus are currently low, but there are reports of emerging resistance, including multi-azole resistant isolates in parts of Europe.
Collapse
|
26
|
Rudramurthy SM, Chakrabarti A, Geertsen E, Mouton JW, Meis JF. In vitro activity of isavuconazole against 208 Aspergillus flavus isolates in comparison with 7 other antifungal agents: assessment according to the methodology of the European Committee on Antimicrobial Susceptibility Testing. Diagn Microbiol Infect Dis 2011; 71:370-7. [DOI: 10.1016/j.diagmicrobio.2011.08.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/04/2011] [Accepted: 08/04/2011] [Indexed: 11/29/2022]
|
27
|
Pfaller MA, Duncanson F, Messer SA, Moet GJ, Jones RN, Castanheira M. In vitro activity of a novel broad-spectrum antifungal, E1210, tested against Aspergillus spp. determined by CLSI and EUCAST broth microdilution methods. Antimicrob Agents Chemother 2011; 55:5155-8. [PMID: 21844312 PMCID: PMC3194992 DOI: 10.1128/aac.00570-11] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 07/25/2011] [Indexed: 02/01/2023] Open
Abstract
E1210 is a first-in-class broad-spectrum antifungal that suppresses hyphal growth by inhibiting fungal glycophosphatidylinositol (GPI) biosynthesis. In the present study, we extend these findings by examining the activity of E1210 and comparator antifungal agents against Aspergillus spp. by using the methods of the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) to test wild-type (WT) as well as amphotericin B (AMB)-resistant (-R) and azole-R strains (as determined by CLSI methods). Seventy-eight clinical isolates of Aspergillus were tested including 20 isolates of Aspergillus flavus species complex (SC), 22 of A. fumigatus SC, 13 of A. niger SC, and 23 of A. terreus SC. The collection included 15 AMB-R (MIC, ≥ 2 μg/ml) isolates of A. terreus SC and 10 itraconazole-R (MIC, ≥ 4 μg/ml) isolates of A. fumigatus SC (7 isolates), A. niger SC (2 isolates), and A. terreus SC (1 isolate). Comparator antifungal agents included anidulafungin, caspofungin, amphotericin B, itraconazole, posaconzole, and voriconazole. Both CLSI and EUCAST methods were highly concordant for E1210 and all comparators. The essential agreement (EA; ± 2 log(2) dilution steps) was 100% for all comparisons with the exception of posaconazole versus A. terreus SC (EA = 91.3%). The minimum effective concentration (MEC)/MIC(90) values (μg/ml) for E1210, anidulafungin, caspofungin, itraconazole, posaconazole, and voriconazole, respectively, were as follows for each species: for A. flavus SC, 0.03, ≤ 0.008, 0.12, 1, 1, and 1; for A. fumigatus SC, 0.06, 0.015, 0.12, >8, 1, and 4; for A. niger SC, 0.015, 0.03, 0.12, 4, 1, and 2; and for A. terreus SC, 0.06, 0.015, 0.12, 1, 0.5, and 1. E1210 was very active against AMB-R strains of A. terreus SC (MEC range, 0.015 to 0.06 μg/ml) and itraconazole-R strains of A. fumigatus SC (MEC range, 0.03 to 0.12 μg/ml), A. niger SC (MEC, 0.008 μg/ml), and A. terreus SC (MEC, 0.015 μg/ml). In conclusion, E1210 was a very potent and broad-spectrum antifungal agent regardless of in vitro method applied, with excellent activity against AMB-R and itraconazole-R strains of Aspergillus spp.
Collapse
Affiliation(s)
| | | | | | | | - Ronald N. Jones
- JMI Laboratories, North Liberty, Iowa 52317
- Tufts University School of Medicine, Boston, Massachusetts 02111
| | | |
Collapse
|
28
|
Targeted disruption of nonribosomal peptide synthetase pes3 augments the virulence of Aspergillus fumigatus. Infect Immun 2011; 79:3978-92. [PMID: 21746855 PMCID: PMC3187245 DOI: 10.1128/iai.00192-11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Nonribosomal peptide synthesis (NRPS) is a documented virulence factor for the opportunistic pathogen Aspergillus fumigatus and other fungi. Secreted or intracellularly located NRP products include the toxic molecule gliotoxin and the iron-chelating siderophores triacetylfusarinine C and ferricrocin. No structural or immunologically relevant NRP products have been identified in the organism. We investigated the function of the largest gene in A. fumigatus, which encodes the NRP synthetase Pes3 (AFUA_5G12730), by targeted gene deletion and extensive phenotypic analysis. It was observed that in contrast to other NRP synthetases, deletion of pes3 significantly increases the virulence of A. fumigatus, whereby the pes3 deletion strain (A. fumigatus Δpes3) exhibited heightened virulence (increased killing) in invertebrate (P < 0.001) and increased fungal burden (P = 0.008) in a corticosteroid model of murine pulmonary aspergillosis. Complementation restored the wild-type phenotype in the invertebrate model. Deletion of pes3 also resulted in increased susceptibility to the antifungal, voriconazole (P < 0.01), shorter germlings, and significantly reduced surface β-glucan (P = 0.0325). Extensive metabolite profiling revealed that Pes3 does not produce a secreted or intracellularly stored NRP in A. fumigatus. Macrophage infections and histological analysis of infected murine tissue indicate that Δpes3 heightened virulence appears to be mediated by aberrant innate immune recognition of the fungus. Proteome alterations in A. fumigatus Δpes3 strongly suggest impaired germination capacity. Uniquely, our data strongly indicate a structural role for the Pes3-encoded NRP, a finding that appears to be novel for an NRP synthetase.
Collapse
|
29
|
Quindós G. Candidiasis, aspergilosis y otras micosis invasoras en receptores de trasplantes de órgano sólido. Rev Iberoam Micol 2011; 28:110-9. [DOI: 10.1016/j.riam.2011.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
|